board: ti: am43xx: add AM437x SK PHY Address

pass correct PHY Address when running on SK
so that we have working ethernet with this board
too.

Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/board/ti/am43xx/board.c b/board/ti/am43xx/board.c
index 6379cef..054a452 100644
--- a/board/ti/am43xx/board.c
+++ b/board/ti/am43xx/board.c
@@ -594,6 +594,11 @@
 		writel(RMII_MODE_ENABLE | RMII_CHIPCKL_ENABLE, &cdev->miisel);
 		cpsw_slaves[0].phy_if = PHY_INTERFACE_MODE_RMII;
 		cpsw_slaves[0].phy_addr = 16;
+	} else if (board_is_sk()) {
+		writel(RGMII_MODE_ENABLE, &cdev->miisel);
+		cpsw_slaves[0].phy_if = PHY_INTERFACE_MODE_RGMII;
+		cpsw_slaves[0].phy_addr = 4;
+		cpsw_slaves[1].phy_addr = 5;
 	} else {
 		writel(RGMII_MODE_ENABLE, &cdev->miisel);
 		cpsw_slaves[0].phy_if = PHY_INTERFACE_MODE_RGMII;